package org.csmzxy.class2333;

public class Work03 {
    public static void main(String[] args) {
        int sum  = 0;
        int arr[] = new int[20];
        for(int i=0;i <arr.length; i++) {
            if (i == 0 || i == 1) {
                arr[i] = 1;
            } else {
                arr[i] = arr[i - 1] + arr[i - 2];
            }
        }
        for(int i = 0;i<arr.length;i++){
            sum = sum + arr[i];
        }
        System.out.println(sum);
    }
}
